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DIY Garmin GPS Internal Battery Replacement

Thought I'd post this for those who own the older Garmin 296's,396's etc
and have been having trouble with the units taking a long time to aquire
satellites, clock displays wrong time and date on boot up. Mine was
taking 30 minutes or so after a couple weeks being turned off. Trouble
is the "internal battery". Figure on start up the gps uses the wrong
date and time to locate the satellites. Now it boots in 15 seconds after
internal battery replacement that cost me about $5.00 bucks and 30
minutes labor. Garmin says it can be done at a cost of $250.00 if you
send the unit in but do it yourself.

I thought I'd pass this on to my fellow pilots......if your interested
here's the link..

Wow I did this to my King Skymap IIIC and it was a piece of cake compared
to the Garmin. They really bury that guy deep !!

You ought to try it on a laptop, and have to take every single board loose,
including the display.

The Garmin looks like a piece of cake, after doing that, recently.

I just took my certified KLN-89B to the shop to have the battery
replaced. $200.00. But, I got about 9 years out of the battery. The
owners manual says to replace every 3 to 5 years. The GPS gave me a low
battery warning. After I did that I didn't realize the GPS had to be set
up again. Not only did I loose flight plans (no big deal), I lost
several set up functions that had to be redone. Took less than an hour
to do after reading the manual.

I just did the swap on my 396. The descriptions in Terry's links give
you a pretty good overall guide, but I will add a few details.

Once you get all the outer case screws out and get the ring nut off off
the BNC connector, the case is held together by the stickiness of the
gasket. I used a plastic iPod case cracker. If you GENTLY wedge a small
flat jeweler's screwdriver in there and wiggle it a bit that should
crack it without bunging up the case. Do it on the bottom so you won't
see any scars you might create.

Once cracked, the instructions in the links tell you to disconnect the
white cable. To do this you have to slide the locking bar about 1/32 of
an inch on both sides. The bar is the small plastic piece right where
the ribbon cable enters the connector. Once you slide it, the cable will
easily slide out. If it is stuck, you have not released the bar
correctly. They slide pretty easily so if it does not move, you are
doing something wrong.

With the white cable disconnected, you can wiggle the screen loose. It
is just laying in there on 4 plastic posts. The instructions on the
links do not say anything about disconnecting the screen cable and show
the screen laying there with the cable stretched out. These cables are
VERY fragile and you must be careful not to pull on it. You CAN
disconnect it as I did, but that connector is very tricky. There is a
black release bar that "flips up" like a soda can pop top. Once done,
the cable will slide out. Whether you disconnect the screen or just
want to flip it and move it out of the way, you do need to disconnect
the 2 wire black/red cable connector. I suggest fingernails or tweezers.
If you pull the wires, you are asking for trouble. Also, these are tight
and need a wiggle. Pull straight up.

The foil on mine was a challenge. There is a plastic protector sheet
behind it and mine was caught underneath the metal frame you are peeling
everything off of.

With the screen moved aside or disconnected and the 4 circuit board
screws removed, there is an additional cable you need to release that
the instructions omit. It is a cable on the side by the BNC connector on
the main board that wraps around the board and goes underneath it. It
uses the same "sliding bar" connector like the white one. Once
disconnected, you should be able to remove the back case from the board.

Once you are facing the battery, there are 3 ways to remove it. One, you
can heat up the solder joints and try to pluck off the metal tab from
the board. Two, you can use a solder sucker. Three, you can use solder
wick. Whatever method you use, be very careful of that tiny little piece
of plastic right next to the negative (towards the center of the circuit
board) solder pad. That is an electronic component (diode or resistor).
If you unsolder that you are likely to have a difficult time replacing
it. It is surface mounted and VERY tiny.

After the old battery is removed, you can try to break off the tabs and
reuse them on the new battery. Or, you can solder fine stiff (insulated
bell) wire to the board and the battery and let the battery sit in the
large space in the case back. Or you can do as the fellow said and
solder a wafer battery holder in there and the next visit to this area
will be a lot easier. I used bell wire. It is stiff enough to hold the
battery away from the circuit board and I could use a battery 15 times
the size (and capacity) as the original. I used a Radio Shack CR 1220.

Putting it back together is the reverse of taking it apart. If you did
opt to disconnect the screen cable, you now have the challenge of
getting it back on correctly. Getting these back in is very difficult
unless you have done them before (iPods have similar connectors inside).
Maneuvering the cable into the connector is tricky enough to tempt you
to manhandle it a bit. DON'T! As I said they are fragile. The little
flip up has to be up (and they tend to fall down). The cable has to go
all the way in before pushing the flip up bar back down.

Final note, Radio Shack is useless. They don't normally stock the wafer
battery holder or the battery mentioned in the links. They also don't
carry the replacement for the Varia MC621 that you are taking out. They
do seem to stock the CR 1220. I'll report back if it works. I figured
any 3V lithium should work.

Good luck with yours.
Mike

Terry wrote:
Thought I'd post this for those who own the older Garmin 296's,396's etc
and have been having trouble with the units taking a long time to aquire
satellites, clock displays wrong time and date on boot up. Mine was
taking 30 minutes or so after a couple weeks being turned off. Trouble
is the "internal battery". Figure on start up the gps uses the wrong
date and time to locate the satellites. Now it boots in 15 seconds after
internal battery replacement that cost me about $5.00 bucks and 30
minutes labor. Garmin says it can be done at a cost of $250.00 if you
send the unit in but do it yourself.

I thought I'd pass this on to my fellow pilots......if your interested
here's the link..

It has been over 10 days since the battery swap out. Went flying over
the past weekend after the GPS sat for nearly a week. The clock was spot
on to the second. The unit acquired in the usual 30 seconds. I was a bit
concerned that the heat required to solder the wires onto the battery
may cause some harm (I used a temperature controlled iron with a thin
pencil tip). I will have to see if the battery hangs in there. Given the
replacement I used was 20 times the size of the original, maybe it will
last longer. Seems the original made it about 2 years.

Good Luck,
Mike

..lots o stuff snipped about how to change the backup battery.
I just did the swap on my 396. The descriptions in Terry's links give
you a pretty good overall guide, but I will add a few details.

"Mike Spera" wrote in message
m...
It has been over 10 days since the battery swap out. Went flying over
the past weekend after the GPS sat for nearly a week. The clock was
spot on to the second. The unit acquired in the usual 30 seconds. I
was a bit concerned that the heat required to solder the wires onto
the battery may cause some harm (I used a temperature controlled iron
with a thin pencil tip). I will have to see if the battery hangs in
there. Given the replacement I used was 20 times the size of the
original, maybe it will last longer. Seems the original made it about
2 years.